Radiation-convertible norbornene polymers

ABSTRACT

Polymers containing a norbornenyl group are readily crosslinked by irradiation to produce insoluble products. The crosslinked products are useful as coatings on wood, metal, etc., as selfsupporting films, wire insulation, for the treatment of fabrics to render them more durable and crease resistant, as well as in the many known areas in which synthetic polymers are employed such as the production of molded and extruded shaped articles.

United States Patent 1 Colomb, Jr. et a1.

[54] RADIATION-CONVERTIBLE NORBORNENE POLYMERS [75] Inventors: Henry Octave Colomb, .112; David John Trecker, both of South Charleston, W. Va.

[73] Assignee: Union Carbide Corporation, New

York,N.Y.

[22] Filed: Sept. 15,1970

[21] Appl. No.: 72,543

. Related US. Application Data [60] Division of Ser. No. 804,279, March 4, 1969, Pat. No. 3,554,886, which is a continuation-in-part of Ser. No. 697,635, Jan. 15, 1968, abandoned.

[52] [1.5. Ci. ..260/80.81, 96/88, 117/1284, 117/132 C,117/138.5, 117/148, 204/l59.l4,

260/17 R, 260/29.6 T, 260/29.6 ME, 260/47 UA, 260/59, 260/75 UA, 260/77.5 AT,

[51] Int. Cl. f. ..C08f 15/40 [58] Field of Search ..260/80.8l, 29.6 T

[ Feb. 6, 1973 [56] References Cited UNITED STATES PATENTS 3,245,928 4/1966 Carlick et a1. ..260/875 X Primary Examiner-William H. Short Assistant Examiner-L. M. Phynes Attorney-Paul A. Rose, Aldo John Cozzi and Francis M. Fazio [5 7] ABSTRACT 1 Claim, No Drawings EtAllillATlON-CONVERTKBLE NQRWORNENE POLYMERS This invention relates to crosslinkable and crosslinked polymers containing the aliphatic norborenyl group as the cross-linking site.

Polymers of norborene have previously been prepared. However, it has not heretofore been known that certain polymers thereof can be crosslinked by irradiation to render them stiffer, stronger and tougher and to enhance their tear and abrasion resistance properties.

It has now been found that certain norbornene polymer can be crosslinked by irradiation. The radiation convertible, crosslinkable polymers are those which have the unsaturated norbornenyl group in the molecule. The norbornenyl group can be in the polymer backbone, in which case we term the polymer a backbone radiation convertible polymer, "or the norborenyl group may be pendant to the polymer backbone, in which case we term the polymer a pendant radiation convertible polymer. These two terms are more fully defined below, and generic thereto the term radiation convertible polymer is used for the purposes of this invention. Thus, wherever the term radiation convertible polymer appears in the description or claims, it encompasses both sub-classes.

Crosslinking of the radiation convertible polymers is induced by radiation. Two types of radiation are suitableionizing radiation, either particulate or non-particulate, and non-ionizing radiation. As a suitable source of particulate radiation, one can use any source which emits electrons or charged nuclei. Particle radiation can be generated from electron accelerators such as the Van de Graaff, resonance transformers, linear accelerators, insulating core transformers, radioactive elements such as cobalt 6t}, Strontium 90, etc. As a suitable source of non-particle ionizing radiation, one can use any source which emits radiation in the range of from about 10 Angstroms, to about 2000 Angstroms, preferably from about 5X10- Angstroms to about 1 Angstrom. Suitable sources are vacuum ultraviolet lamps, such as xenon or krypton arcs, and radioactive elements such as cesium-137, strontium-90, and cobalt-60. The nuclear reactors are also known to be a useful source of radiation. As a suitable source of nonionizing radiation one can use any source which emits radiation of from about 2000'Angstroms to about 8000 Angstroms, preferably from about 2500 Angstroms to about $580 Angstroms. Suitable sources are mercury arcs, carbon arcs, tungsten filament lamps, xenon arcs, krypton arcs,sunlamps, lasers, and the like. All of these devices and sources are well known in the art and those familiar with the technology are fully aware of the manner in which the radiation is generated and the precautions to be exercised in its use.

As is known, irradiation of a polymer with a Van de Graaff accelerator is generally completed in a matter of seconds, even at the highest megarad dosages used in the examples hereimThis is to be compared to irradiation periods of hours when a mercury arc is the'source of energy.

The ionizing radiation dosage necessary to effect cross-linking will vary depending upon the particular polymer that is undergoing radiation, the extent of crosslinking desired, the number of crosslinkable sits available and the molecular weight of the starting polymer. The total dosage will be from about 10 rads to 10 rads, preferably from 5 X10 rads to 10 rads. A rad is ergs of ionizing energy aborbed per gam of mteil being irradiated.

The radiation is carried out at a temperature below the decomposition temperature of the resin undergoing treatment, generally it is preferably from about 80C. to about (IC.

To prevent undesirable side reactions, an inert atmosphere is present; however, this is not critical and the reaction can be carried out under ambient atmospheric conditions. 4

The crosslinkable norbornenyl polymer can be ir-- radiated in bulk, in solution, in emulsio or dispersion, as a finely ground material or formed article, as a selfsupporting film, as a coating or film on a substrate such as a fabric, wood, glass, metal, etc., or in any other form. In a typical operation the crosslinkable radiation convertible polymer is exposed to the chosen radiation source for the selected period of time until the desired amount of crosslinking has taken place. The intensity of the radiation will effect the time needed to achieve a desired amount of crosslinking. If desired a known photosensitizer such as acetophenone, propiophenone, acetone, xanthone, and'the like, can be present to accelerate the crosslinking reaction when ultraviolet or visiable light are the radiation source. These photosen sitizers are generally present at concentrations below about 10 percent by weight and can be as low as 0.05 per cent. The extent to which crosslinking occurs can be determined from the amount of insolubilization that is observed or the increase in the weight average molecular weight. The greater the amount of insoluble polymer, the greater is .the extent of crosslinking achieved, and the per cent insolubilization is considered to be the extent of crosslinking achieved.

In the specification the compounds are discussed as the norbornene compounds having the basic ring structure for purposes of simplicity and description solely. Equally suitable, and included within the scope of this invention, however, are the tetracyclo compounds of the ring structure and the specification and claims should so be read. The F q sss arewbssnsris t thss ne iq ssw e in which y is 0 or 1.

The principal unobvious and unexpected advantages observed with these polymers are their remarkable susceptibility to radiation-induced curing, their oxidative stability (hence, they are stable and curing can be brought about when desired) and their equal ease of crosslinking by several modes of initiation (electrons, x-rays, photons, etc.). These features render them superior to known classes of radiation-sensitive groups on polymers, e.g., cinnamates, stilbenes, and benzylidene phenones. Moreover, all of these known classes of polymers contain aromatic rings and are, therefore, less stable to prolonged exposure to light then the norborenyl-containing systems, which have enhanced light stability. Other advantages of the norborenyl-containing polymers are improved economics and greater versatility in preparing a broad spectrum of polymer types.

The norbornenyl-containing radiation convertible polymers also have important and unexpected advantages over heretofore used conventional polymers containing added curing promoters(e.g., allyl cyanamate, allyl acrylate). Among these advantages are the fact that lower doses of radiation are required to achieve high levels of crosslinking and that no residual additives remain after curing to contaminate the polymer.

Moreover, radiation curing of the norbornenyl-containing polymers is particularly advantageous in comparison to nonradiative methods of curing e.g., thermal, peroxides, protonic acids, Lewis acids, etc.). This is because radiation curing can be run at low temperatures and under generally mild conditions; with 6 no additives, which may later act as contaminants; with on-off control, which allows greater control over the degree of cross-linking; and at great processing speeds, thereby offering higher productivity and improved economics.

BACKBONE RADIATION CONVERTIBLE Radiation convertible polymers in which the norbornenyl group is in the polymer backbone can be produced directly or indirectly. This class of radiation convertible polymers contains the following divalent norbornenyl structures:

however, they are included within the scope of the invention.

BACKBONE RADIATION CONVERTIBLE POLYESTER POLYMERS The backbone radiation convertible polyester polymers can be produced directly by means of known reactions using a norbornene dicarboxylic acid, ester, ester chloride or ester dichloride of the formula:

or a dihydroxyl norbornene of the formula:

7 or a norbornene hydroxyl acid, ester or ester chloride of the formula:

III

CxHu OH C Hz COR in which x is an integer having a value of from 0 to about 5 and Ris hydroxyl or alkoxyl of from 1 to about 3 carbon atoms or chlorine.

Polyesters can be produced by the self-condensation of the norbornene hydroxyl acids (III), alone or with other hydroxyl acid compounds. Polyesters can also be produced by the condensation of a mixtre of the norbornene dicarboxylic acid compounds (I) with dihydroxyl norbornenes (II). In addition the polyesters can be produced by the reaction of the norbornene dicarboxylic acid compounds (I) with other aliphatic diols, alone or in admixture with other known dicarboxylic acids or esters. Further, the polyesters can be produced by the reaction of the dihydroxyl norbornenes (II) with other known dicarboxylic acids, either alone or in admixture with other known aliphatic diols. These procedures are known in the art.

In a typical method for the production of polyesters, the calculated amounts of carboxylic acid compounds, hydroxyl compounds and catalyst are charged to a reactor and heated in an inert atmosphere at a temperature below the decomposition temperature of the initial reactants. This is preferably from about C. 0 about 250C. It is conventional to use an exce of the least expensive compound, which excess can readily be determined since the reaction between the hydroxyl group and the carboxyl group roceeds in a stoichiometric ratio to form the ester group. If desired the pressure can be reduced to remove low boiling components and to complete the polycondensation reaction. The total esterification time is known to vary since it is dependent upon such variables as the catalyst, starting monomers, pressure, temperature, size of batch, etc. The catalyst is generally present at a concentration of from about 0.001 per cent to about 1 per cent, preferably from about 0.005 per cent to about 0.3 per cent, based on the weight of the carboxylic acids charged. Among the known polyesterification catalysts one can mention antimony oxide, zinc acetate, manganese acetate, cobaltous acetate, zinc succinate, zinc borate, magnesium methoxide, sodium methoxide, barium oxide, cadmium formate, litharge, dibutyltin oxide, tetraisopropyl titanium silicate, and the like.

Illustrative of conventional diols useful for the production of the backbrone radiation convertible polyesters are the aliphatic diols represented by the general formula I'IOC,,I-l,, OH in which n is an integer of from 2 to about 10, such as ethylene glycol, trimethylene glycol, pentamethylene glycol, hexamethylene glycol, decamethylene glycol, and the like. Also suitable are 1,4-hydroxybenzyl alcohol, and the like. It is known that any diol of an aliphatic nature, whether or not it contains aromatic nuclei can be used in the production of polyesters. Thus, the term aliphatic diols includes all those diols of an aliphatic nature which are known in the art to be suitable.

The use of the norbornenyl acid chlorides in producing polyesters is advantageous since lower temperatures can be used in the condensation reaction. Thus,po1yesters can be produced by the condensation of a norbornene dicarboxylic acid chloride (1) with dihydroxyl norbornenes (II). in addition the polyesters can be produced by the reaction of the norbornene dicarboxylic acid chloride (1) with other aliphatic diols, alone or in admixture with other known dicarboxylic acid chlorides. Further, the polyesters can be produced by the reaction of the dihydroxyl norborenes (H) with other known dicarboxylic acid chlorides, either alone or in admixture with other known aliphatic diols.

A typical method for the production of polyesters from dicarboxylic acid chlorides and hydroxyl compounds combines approximately equivalent quantities of each-in a reaction medium or solvent containing an acid-binding agent. The esterification is accomplished by heating the mixture to an elevated temperature. Since the reaction takes place under very mile conditions especially high temperatures are not necessary, 65l50C, for example, being the preferred range of reaction temperatures.

The reaction medium may be a diluent or solvent, it is preferable that at least the starting materials be dissolved at the reaction temperature. Suitable as a reaction medium or solvent are aliphatic and aromatic hydrocarbons such as, cyclohexane, heptane, benzene, toluene, tetrahydronapthalene or curnene, halogenated hydrocarbons such as, chloroform, tetrachloroethylene, v monochlorobenzene, orthodichlorobenzene, trichlorobenzene, ethers such ad diphenyl ether, diisopropyl ether, N,N-dialkyl amides such as dimethyl formamide, dimethyl acet amide and alkyl sulfoxides such as dimethyl sulfoxide and tetramethylene sulfoxide. The N,N-dialkyl amides are preferred owing to their catalytic effect and faborable solvent power. I

As acid binding agents, there are suitable, for example, pyridine and its homologues, furthermore N,N-dialkyl anilines, especially diethyl aniline, isoquinoline and other stable heterocyclic nitrogen bases. Aliphatic or cycloaliphatic tertiary amines can also be used, for example, triethylamine, triethylene diamine, N-methylpiperidine and N-butylpyrrolidine. Also nonbasic hydrogen halide acceptors may be used such as acrylonitrile and acylethyleneimidess especially alkyl or arylsulfethyleneimide.

The conventional carboxylic acids useful for the production of the radiation convertible polyesters are well known to those skilled in the art. The most widely used is terephtalic acid and the dialkyl esters thereof, such as dimethyl terephthalate, in which the alkyl group contains from one to about five carbon atoms. Other known dicarboxylic acids or their esters include isophthalic acid, p,p'-diphenylcarboxylic acid, p,p'- dicarboxydiphenyl ethane, p,p'-dicarboxydiphenyl hexane, p,p'-dicarboxydiphenyl sulfide, p,p'-dicarboxydiphenyl ether, p,p'-dicarboxyphenoxy butane, 2,6-dinaphthalene dicarboxylic acid, and the like. These aromatic acids can be used aline or in admixture, and up to about 20 per cent by weight of the aromatic acid can be replaced by an aliphatic dicarboxylic acid or ester thereof, such as adipic acid, succinic acid, sebacic acid, dimethyl 1,20-eicosane dioate, and the like.

Illustrative of known hydroxy acids that can be used in the production of the radiation convertible polyesters one can mention 4-hydroxybenzoic acid, 4- hydroxybutric acid, IO-hydroxydecanoic acid, 3- hydroxy-2,2-dimathylpropi0nic acid, as well as the esters thereof, for example, 2,2-dimethyl-3-hydroxypropyl 2,2-di-methyl-3-hydroxypropionate.

Suitable norbornene compounds for the production of the radiation convertible polyesters include 5,6- dicaroxybicyclo- [2.2.1]hept-3-ene; the dimethyl, diethyl, dipropyl, diisopropyl, dibutyl, diisobutyl, ditertiarybutyl, and dipentyl esters of 5,6-dicarboxybicyclo]2.2.l]hept-3-ene; the dicarboxyalkylbicyclo- [2.2.1]hept-2-enes such as 5,6-dicarb0xymethylbicyclo[3.3.l hept-2-ene, 5 ,6-di-(2-carboxyethyl)bicyclo[2.2.l]hept-Z-ene, 5,6- di-(B-carboxypropyl)bicyclo[2.2.1]hept-Z-ene, 5,6-di-(2-carboxypropyl)bicyclo[2.2.l]-hept-2-ene, the 5,6-dicarboxybutylbicyclo- [2.2.1]hept-2-enes, 5-carboxyethyl-6- carboxypropylbicyclo- [2.2.l]-hept-2-ene, S-carboxymethyl-6-carboxypentylbicyclo[2.2.l hept-Z-ene, 5- carboxy-6-carboxymethylbicyclo[2.2.l ]hept-Z-ene, the 5,6-dicarboxypentylbicyclo[2.2.1]hept-2-enes, 5,6- di(carboxy-2- ethylhexyl)bicyclo[2.2.l ]hept-Z-ene, the 5,o-dicarboxydecylbicyclo- [2.2.1]hept-2-enes; the alkyl esters of said 5,6-dicarboxyalkylbicyclo[2.2.l ]hept-Z-enes; 5,6-dihydroxybicyclo[2.2.l ]hept-Z -ene; the lower fatty acid esters such as the acetoxy, propionoxy, butyryloxy, pentanoyloxy esters of 5,6- dihydroxybicyclo[2.2.l]hept-Z-ene; the 5,6-dihydroxyalkylbicyclo- [2.2.1]hept-2-enes such as 5,6- dihydroxymethylbicyclo[2.2.l]- hept-Z-ene, 5,5- dihydroxymethylbicyclo[2.2.l-]hept-2-ene, 5,6- di-(2- hydroxyethyl)bicyclo[2.2.1]hept-Z-ene, 5-hydr0xy-6- hydroxethylbicyclo[2.2.1 ]hept-Z-ene, S-hydroxymethyl-o-hydroxybutylbicyclo[2.2.1]hept-2-ene, the 5,6-dihydroxypropylbicyclo[2.2.l]- hept-Z-enes, the 5 ,G-dihydroxypentylbicyclo[2.2.1]hept-Z-enes, the 5,6-dihydroxybutylbicyclo[2.2.l ]hept-Z-enes, the 5,6- dihydroxyisopropylbicyclo[ ]hept-Z-enes; the lower fatty acid esters of said 5,6-dihydroxyalkylbicyclo[2.2.l]hept-Z-enes; S-hydroxy- 6-carboxybicyclo[2.2.l]hept-Z-ene; the lower monoand diesters of said 5-dydroxy-6-carboxybicyclo[2.2.1]hept- 2-3ne such as 5- carboxy-G-acetoxybicyclo[2.2.l]hept- 2-ene, 5-carboxy-6-propionoxybicyclo[2.2. l ]hept-Z- ene, 5-carboxy6-butyryloxybicyclo[ 2.2.11- hept-2- ene, 5-acetoxy-6-carbomethoxybicyclo[2.2.l]hept-2- ene, 5-acetoxy-6-carbopentoxybicyclo[2.2.1]hept-2- ene, 5-pentanoyloxy- 6-carbomethoxybicycio[2.2.1 ]hept-2-ene, 4-butyryloxy-6-carbopropoxybicyclo[ 2.2.l]hept-2-ene, 5-hydroxy-6-carbomethoxybicyclo- [2.2.1]hept-2-ene, 5-hydroxy-6-carbopropoxybicyclo[ 2.2.l1hept-2ene, 5-hydroxy-6-carbopentoxybicyclo[ 2.2.l1hept-2-ene; the 5-hydroxyalkyl-Gcarboxyalkylbicyclo[2.2.l ]hept-Z-enes such as 5-hydroxymethyl-6- carboxymethylbicyclo[2.2.l ]hept-Z-ene, S-hydroxymethyl-6- carboxypentylbicyclo[2.2.l]hept-Z-ene, 5-

hydroxypentyl-6-carboxypentylbicyclo[2.2.l ]hept-Z ene, -hydroxypropyl-6-carboxypropylbicyclo[ 2.2.1 ]hept-Zene; the lower monoand di-esters of said 5-hydroxyalkyl-6-carboxyalkylbicyclo[ 2.2.1 ]hept-Z- enes such as 5- acetoxymethyl-6-carboxymethylbicyclo[2.2.l ]hept-Z-ene, 5-butyryloxymethyl-6-carboxyethylbicyclo[2.2.l]hept-Z-ene, S-acetoxypropyl- 6-carboxypropylbicyclo[2.2.l ]hept-Z-ene, S-acetoxymethyl-6-carbomethoxymethylbicyclo[2.2.l ]hept-Z- ene, 5propionoxyethyl-6- earbomethoxyethylbicyclo[ 2.2.1 ]hept-2-ene, 5-acetoxypentyl-6- carbobutoxypropylbicyclo[2.2.l]hept-2-ene, 5-hydroxmethyl-6- carbomethoxymethylbicyclol2.2.l]hept-Z-ene, S-hydroxypropyl-6- carbomethoxymethylbicyclo[2.2.l]hept-2- ene, 5-hydroxypentyl-6- carbopropoxypropylbicyclo[ 2.2.1]hept-2ene, 5-hydroxyethyl-6- carbobutoxymethylbicyclo[2.2.l]hept-Z-ene, 5-hydroxyethyl-6- carbomethoxypentylbicyclo[]hept-2-ene; and the like.

These compounds are readily produced by the Diels- Alder reaction of cyclopentadiene with the appropriate ethylenically unsaturated compound as disclosed in US. Pat. No. 2,340,908.

in the production of the radiation convertible polyesters, the norbornene compound defined by Formulas I, II and [II can be the sole reactant of that particular class necessary for the production of the polyester or it can be any lesser amount. Preferably, however, the norbornene compound is used at a concentration of about 5 mole per cent or more of the radiation convertible polyester produced and preferably from about 10 mole per cent to about 50 mole percent of the polyester. It has been observed that crosslinking occurs at a more rapid rate as the concentration of the norbornenyl compound is increased since the number of crosslinking sites is correspondingly higher. As is obvious to those skilled in the art, the maximum, theoretical mole per cent possible when one is using a dicarboxylic acid compound of Formula I is 50 mole percent since an equal molar quantity of diol is necessary to react with the norbornenyl dicarboxylic acid or ester; the same maximum applies when one is using a dihydroxyl norbornene of Formula II since an equal molar quantity of dicarboxylic acid or ester is necessary to react with the dihydroxyl norbornene compounds. However, since the norbornene hydroxyl acids of Formula III can self-condense, such compounds can be used at a molar concentration of 100 per cent.

Illustrative examples of backbone polyester radiation convertible polymers are the polyesters produced from the following combinations of reactants. The figures in the parenthesis represent the mole per cent of that particular compound charged when a mixture of that class of compound was used, this mole per cent is based on the total molar amount of that class of compound involved, whether it be dicarboxylic acid compounds, dihydric compounds, or hydroxyl acid compounds.

1. 5,6-dicarboxybicyclo[2.2.l ]hept-Z-ene,

ethylene glycol.

2. 5,6-dicarboxybicyclo[2.2.l ]hept-2-ene (40),

dimethylterephthalate (60-, ethylene glycol.

3. dimethylester of 5,6-dicarboxybicyclo[2.2. l ]hept- 6 2-ene (50), dimethylterephthalate (50),

ethylene glycol.

5,6-dicarboxymethylbicyclo[2.2.1]hept-2-ene dimethylterephthalate (80), ethylene glycol. 5. diethylester of 5,6-dicarboxymethylbicyclo[2.2.l

]hept-2-ene (30) dimethylterephthalate ethylene glycol 5 ,6-dihydroxybicyclo[2.2.l ]hept-Z-ene dimethylterephthalate. 7. 5,6-diacetoxybicyclo[2.2.1 ]hept-2-ene isophthalic acid. 8. 5,6-dihydroxybicyclo[2.2.l ]hept-Z-ene terephthalic acid (90) p,p-diphenylcarboxylic acid l0). 5,6-dihydroxybicyclo[2.2.l ]hept-Z-ene (25) ethylene glycol dimethylterephthalate.

10. 5,6-dihydroxymethylbicyclol2.2.l]hept-2-ene ethylene glycol (70) dimethylterephthalate.

l 1. 5 ,6-diacetoxymethylbicyclo[2.2.1]hept-Z-ene ethylene glycol 90) dimethylterephthalate.

l2. 5-hydroxy-6-carboxybicyclo[2.2.l ]hept-2-ene.

l3. 5-hydroxy 6-carboxybicyclo[2.2.1]hept-2-ene 3-hydroxypropionic acid 14. 5-carboxy-6-acetoxybicyclo[2.2.l ]hept-2-ene 7-hydroxypentaonic acid 15. 5-acetoxy-6-carbomethoxybicyclo[2.2.l ]hept-2- ene (50) p-hydroxybenzoic acid (50).

16. S-hydroxy-6-carbomethoxybicyclo[2.2.l ]hept-2- ene (40) o-hydroxyhexanoic acid (60).

17. 5 -hydroxymethyl-6-carboxymethylbicyclo[ 2.2.1 ]hept-Z-ene (50) 6-hydroxyhexanoic acid (50).

18. 5-acetoxymethyl-6-carboxymethylbicyclo[ 2.2.1 ]hept-Z-ene (50) 6-hydroxyhexanoic acid (50).

19. 5-acetoxymethyl-6-carbomethoxymethylbicyclo[ 2.2.1 ]hept-2-ene (50) 7-hydroxypentanoic acid (60).

20. 5-hydroxymethyl-6-carbomethoxymethylbicyclo[2.2.l1hept-2-ene (50) 7-hydroxypentanoic acid (50).

5,6-dicarboxybicyclo[2.2.l ]hept-2-ene 5 ,6-dihydroxybicyclo[2.2.l ]hept-Z-ene.

22. 5,6-dicarboxymethylbicyclo[2.2.l ]hept-2-ene 5 ,6-dihydroxybicyclo[2.2.l ]hept-Z-ene.

23. diemthylester of 5,o-dicarboxyethylbicyclo[2.2.l ]hept-2-ene I 5 ,6-dihydroxybicyclo[2.2.l ]hept-2-ene.

24. 5-hydroxy-G-carboxybicyclo[2.2.l ]hept-2-ene 5-hydroxy-6-carbopropoxybicyclo[2.2.l ]hept-2- ene.

The backbone radiation convertible polyesters can range from low average molecular weight polymers of about 750 to high average molecular weights up to about 100,000 or higher.

BACKBONE RADIATION CONVERTIBLE POLYAMIDE POLYMERS The backbone radiation convertible polyamide polymers are producedirectly by means of known reactions using a norbornene dicarboxyiic acid compound of Formula 1, or a diamino norbornene of the formula:

or a norbornene amino acid of the formula X Ex E in which R is hydrogen or alkyl of from one to about three carbon atoms.

Radiation convertible polyarnides can be produced by the self-condensation of the norbornene amino acids (V), alone or with other amino acid compounds. The polyamides can also be produced by the condensation of a mixture of the norbornene dicarboxylic acid compounds (1) with diamino norbornenes (1V) or with other known diamino compounds known to be useful in the production of polyamides. Further, the polyamides can be produced by the reaction of the diarnino norbornenes (IV) with other known dicarboxylic acids, either alone or in admixture with other known diamines. I

The production of polyamides is well known to those skilled in the art, as is the calculation of the proportions of the reactants to be charged. The selected reactants are generally heated at reduced pressure under an inert gas atmosphere while removing water of condensation; catalysts are used to increase the rate of reaction. The temperature of the initial reactants.

The backbone radiation convertible polyamide polymers may also be produced by a heterogeneous or interfacial polymerization process whereby a polyamine is caused to react with a dicarboxylic acid chloride in a system in which the reactants are in solution in'mutually immiscible solvents and the solution of one of the reactants is dispersed in the solution of the other. This process may be carried out either as a batch process or as a continuous process, and is clearly described in British specification No. 737,184, which is hereby incorporated by reference. This patent also discloses many suitable amine compounds.

The preferred conventional dicarboxylic acids that can be used are the alpha, omega alkanedioic acids containing from about six to about 20 carbon atoms such as hexanedioic acid, octanedioic acid, nonanedioic acid, henedecanedioic acid, dodecanedioic acid, hexadecanedioic acid, eicosanedioic acid, and the like.

The known conventional diamines include 1,6-hexanediamine, 1,8-octanediamine, 1,9-nonanediamine, 1,12-dodecanediamine, 1,14-tetradecanediamine, and the like.

Suitable known amino acids include -aminohexanoic acid, 7-aminoheptanoic acid, lO-aminodecanoic acid, -aminopentadecanoic acid, and the like.

The radiation convertible polyamide polymers can also be produced by reacting the norbornene comene, 5-aminopentyi-6-carboxybicyclo[2.2.1]hept-2- ene, 5-amin0-6-carboxym ethylbicyclo[2.2.1]hept52- ene, 5-amino 6-carboxypropylbicyc1o[2.2.1]hept-2- cue; the acid chlorides of said 5-amino-6-carboxybicyc1o[2.2.1 lhept-Z-ene compounds, and the like.

The concentration of norbornene compound used in producing the radiation convertible polyamide canvary from about 5 mole per cent to 100 mole per cent. When one is using either a norbornene dicarboxylic acid of formula 1 or a norbornene diamino compound of the Formula IV the theoretical maximum mole per' cent of each charged is 50 mole per cent, whereas one can use up to 100 mole per cent of a norbornene amino acid of Formula V, these mole ratios are based on the total moles of reactants charged. illustrative radiation convertible polyamides are the polymers produced from the following combinations of reactants. The parenthetical figure is the mole per cent of that particular compound charged when a mixture of that class of compound is used, this mole per cent is based on the total molar amount of that class of compound involved, whether it be dicarboxylic acid cornpound, diamino compound, or mino acid compound.

25. 5,6-dicarboxybicyclo[2.2.1lhept-Z-ene 1,6-hexanediamine.

26. 5,6-dicarboxybicyclo[2.2.l']hept-2-ene (50) 1,6-hexanedioic acid (50) 1,6-hexanediamine.

27. 5,6-dicarboxybicyclo[2.2.1]hept-2-ene.(50)

1,6-hexanedioic acid (50) 5,6-diaminobicyc1o[2.2.l ]hept-2-ene (50) 1,6-hexanediamine( 50).

28. 5,6-dicarboxyethylbicyclo[2.2.1]hept-2-ene 1,1 Z-dodecanediamine (50) 5,6-diaminoethy1bicyc1o[2.2.1lhept-Z-ene (50).

29. diacid chloride of 5,6-dicarboxymethylbicyclo[ 2.2.11hept-2-ene I 1,10-decanediamine.

30. 5,6-diaminopropy1bicyclo[2.2.1lhept-Z-ene (25) 1,8-octanediamine 1,6-hexanedioic acid.

31. 5-amino-6-carboxybicyc1o[2.2.1]hept-2-ene.

32. S-amino-6-carboxybicyclo[2.2 .1lhept-Z-ene l-aminodecanoic acid.

33. 5-aminomethyl-o-carboxybicyclo[2.2.l]hept-2- ene epsilon-caprolactone.

34. S-aminc-6-carboxyethy1bicyc1o[2.2.1]hept-2- ene 6-amionhexanoic acid.

aminopentyl-6-carboxybicyc1o[2.2.1]hept-2-hept-2- 35. 5,6-dicarboxybicyclo[2.2.l ]hept-2-ene epsilon-caprolactam.

The molecular weight of the polyamides can be controlled by known procedures and can vary from about 750 to about 100,000 or more.

BACKBONE RADIATION CONVERTIBLE POLYETHER POLYMERS The backbone radiation convertible polyethers can be readily produced by the catalytic reaction of an oxirane compound such as ethylene oxide, 1,2-propyelen oxide, 1,2-butylene oxide, 2,3-butylene oxide, styrene oxide or mixtures thereof with any of those norbornene compounds defined by Formulas I to V inclusive which have a reactive hydrogen atom. The polyether adducts can have'molecular weights of from about 200 to about 10,000, preferably from about 750 to about 5,000. It is known that the molecular weight of such adducts can be controlled by controlling the amount of oxirane compound added.

In an embodiment for the production of the radiation convertible polyethers, one mole of 5,6-dihydroxymethylbicyclohept-Z-ene and 0.l mole of powdered potassium hydroxide are placed in an autoclave, which is sealed, purged with nitrogen and heated. Then from about 20 to 200 moles, or more, of alkylene oxide are fed to the autoclave at a rate to maintain a temperature of about 110 to 120C. At the completion of the oxide feed,-the autoclave temperature is maintained at about 100C. until constant pressure is achieved to complete the reaction. The crude product is neutralized, refined with calcium, magnesium or aluminum silicate, and filtered.

Illustrative of backbone radiation convertible polyethers are the polyethers produced frm the following combinations of reactants. In this instance the parenthetical figure represents the moles of alkylene oxide compound charged.

36. 5,6-dicarboxybicyclo[2.2.1]hept-2-ene ethylene oxide (20).

37. 5 ,6-dicarboxymethylbicyclo[2.2.l ]hept-2-ene ethylene oxide (20) propylene oxide (30).

( 5,6-dihydroxybicyclo[2.2.1lhept-2-ene ethylene oxide (100).

39. 5,6-dihydroxyethylbicyclo[2.2.l ]hept-2-ene ethylene oxide (50) styrene oxide 40. Shydroxy 6-carboxybicyclo[2.2.1lhept-Z-ene ethylene oxide (9) 1,2-butylene oxide 10). 41. S-hydroxy .methyl-6-carboxyethylbicyclo[2.2.1

lhept-Z-ene ethylene oxide (150). I 42. 5,6-diaminobicyclo[2.2.l lhept-Z-ene ethylene oxide (150). propyelen oxide (50).

43 5 ,6-diaminomethylbicyclo[ 2.2.1 lhept-2-ene propyelen oxide (75 44. S-amino-6-carboxybicyclo[2.2.l Ihept-Z-ene ethylene oxide (40) propylene oxide (40). 45. S-aminoethyl-6-carboxybicyclo[2.2.l lhept-Z- ene ethylene oxide (50).

46. 5-amino-6-carboxypropylbicyclo[2.2.1]hept-2- ene ethylene oxide (20).

The backbone radiation-convertible polyethers can also be readily produced by the copolymerization of an oxacyclo compound such as ethylene oxide, 1,2- propylene oxide, 1,2-butylene oxide, 2,3-butylene oxide, styrene oxide, cyclohexene oxide, 3,3-bis- (chloromethyl)oxacyclobutane, 3,3-bis(methyl)oxacyclobutane, 3,3-bis(fluoromethyl)oxacyclobutane, tetrahydrofuran, 7-oxabicyclo-[2.2.l]heptane or mixtures thereof with a norbornene oxyacyclo compound of formula V1 where y is 0 or 1, of formula Vll VII CHR'

sax-l) where z is 0 to 2 and R is hydrogen or alkyl of one to three carbon atoms. The polyether polymers can have molecular weights of from about 200 to about 100,000 or higher, preferably from about 750 to 50,000.

In the production of polyethers, the desired amounts of liquid organic reaction medium, monomers and catalyst are charged to a polymerization vessel in an inert atmosphere and maintained at a temperature of from 1 10C. to about 200C., preferably from about 30 to C. until the polymerization reaction is complete. The product is recovered by evaporation of solvent, filtration or precipitation with a nonsolvent and filtration. The crude product is washed with nonsolvent to remove catalyst residues, unreacted monomer and residual solvent and then dried.

The liquid organic reaction medium may be a solvent or a nonsolvent for the monomers, which is inert to the monomers and to the catalyst, and which remains liquid under the conditions used in the polymerization. Usefully employable media are the ethers, such as diethyl ether and dimethyl ether, aromatic hydrocarbons, such as benzene, toluene and xylene, chlorinated hydrocarbons such as methylene chloride, aliphatic hydrocarbons, and cycloaliphatic hydrocarbons. The preferred reaction media are the hydrocarbons and chlorinated hydrocarbons containing one to 10 carbon atoms in the molecule.

The amount of reaction medium is not critical and is determined only by preference. The amount of reaction medium may be very small or negligible compared to the final polymer which is formed in which case the product mixture is solid or very thick and difficult to handle, and on the other hand the employment of very large amounts of reaction medium compared to the polymer which is formedakes recovery of the polymeric product difficult. Generally from 0 to 1000 parts of reaction medium per part of polymer formed are employed, preferably from 4 to 100 parts of reaction medium are used.

The catalyst is generally present at a concentration of from 0.0001 per cent to about 10 per cent, preferably from about 0.005 to 0.5 per cent based on the weight of monomers charged. Such catalyst include one can mention for example: a) strong bases such as the alkali and alkaline earth metal oxides, hydroxides, alkoxides, phenoxides, amides, amide-alkoxide and hexammoniate; b) alcoholates and phenolates of various metals such as Fe(OR") Ti(OR"),, Sn(OR") AI(OR") and the like, wherein R" is 7kyl or aryl, and the reaction products of alcoholates with water, carboxylic acids, metal salts, beta-diketones, and 2-(N,N- dialylamino)alkanols, such as the well known chelates of tienium obtained by said or equivalent procedures; salts of organic acids with a variety of metals such as alkali metals, alkaline earth metals, al. Sn, Pb, Mn, Co, Ni and Cu, including for example, sodium acetate, calcium oxalate, stannous oxalate, stannous octoate, stannous laurate, lead octoate, metallic driers such as manganese and cobalt naphthenate, and the like; (1) organo-metallic derivatives of the metals of groups I, II and III of the Periodic Table such as butyl lithium, tributyl boron, triethyl aluminum, diethyl aluminum chloride, dibutyl aluminum ethoxide, diphenyl aluminum hydride, dibutyl zinc, diisobutyl cadmium, reaction products of these compoudns with water, alcohols, metal halides, metal oxides, chelating agents such as acetylacetone, benzoylacetone, diethylmalonate and chelated compounds of the ransition metals; e) Lewis acids such as boron trifluoride, phosphorus pentafluoride, sulfur trioxide, aluminum chloride, ferric chloride, stannic chloride, antimony pentachloride and the like; i) oxonium salts such as triethyloxonium hexachloroantimoniate, and the like.

The best results from the standpoint of polymer yield are obtained when the polymerization is effected under anhydrous, non-oxidizing conditions. A convenient way for obtaining such conditions is by sweeping the system with a dry, inert gas and polymerizing under a blanket of inert gas. A suitable inert gas is nitrogen.

Illustrative of radiation-convertible polyethers are the polymers produced from the following reactant combinations. In this group of examples the parenthetical figure represents the parts by weight of that particular reactant. V

47. Propylene Oxide (100 3-Oxatricyclo[3.2.l.0]Oct. 6-ene (20) Dibutyl zinc (l) 48. 3,3-bis(chloromethyl)oxacyclobutane spiro[(bicyclo[2.2.l ]hept-2-6,3-( l -oxacyclo-butane)] (5) Methyl chloride (100) Phosphorus pentafluoride (0.1)

49. 3-Oxatricyclo[4.2.l.0'- ]n0n-7-ene (l0) Toluene (50) Diethyl zinc (.08 )-water (.01)

50. Tetrahydrofuran (100) 4-Oxatricyclo[5.2.l.0'-]Dec. 8-ene Triethyloxonium hexachloroantimoniate (l) 51. Cyclohexene Oxide (l0) 3-Oxatricyclo[3.2.l.0"]Oct. 6-ene (3) Toluene (20) Triethyl Aluminum (.1 )-water (.02)

BACKBONE RADIATION CONVERTIBLE URETHANE POLYMERS The backbone radiation convertible urethane polymers can be produced by known reactions; these polymers can be elastomers when produced in the absence of a blowing agent or cellular when produced using any of the known blowing agents.

The conventional organic polyisocyanates that can be used to produce the urethane polymers include the isocyanates such as ethylene diisocyanate, trimethylene diisocyanate, hexamethylene diisocyanate, propylene- 1,2-diisocyanate, ethylidene diisocyanate, cyclopentylene-l,3-diisocyanate, the 1,2-, 1,3- and 1,4- cyclohexylene diisocyanates, the 1,3- and 1,4-phenylene diisocyanates, polymethylene polyphenyleneisocyanates, the 2,4-and 2,6-tolylene diisocyanates, the 1,3- and 1,4-xylene diisocyanates, bis(4-isocyanatophenyl)methane, 4,4-diphenylpropane diisocyanates, the polyisocyanates disclosed in U.S. Pat. No. 2,683,730, bis(2'isocyanatoethyl)carbonate and the like. The norbornene isocyanates are those compounds of the formulas:

VIII

-o,HhNc o o,H3XNo o and VIIIA and include 5,6-bicyclo[2.2.l ]hept-Z-ene diisocyanate, 5,6-diisocyanatomethylbicyclo[2.2.1]hept-2-ene, 5,6- disocyanatobutylbicyclo[2.2.l]hept-Z-ene, bis(2-isocyanatoethyl)bicyclo[2.2.1]-hept-5-en-2,3-dicarboxylate, -5 ,6-diisocyanatopentylbicyclo[2.2. l ]-hept-2-ene, and the like as disclosedin U.S. Pat. No. 3,275,679. The isocyanates can be usedalone or in combination.

The polyisocyanates described supra react with compounds containing a reactive hydrogen atom as deter mined by the Zerewitinoff method to produce urethane polymers. The norbornene isocyanates of Formulas VIII and VIIIA can react with the previously described radiation convertible polyester polymers and radiation convertible polyether polymers to produce radiation convertible urethane p olymers. Radiation convertible uretane plymers are also produced by the reaction of norbornene isocyanates of Formulas VIII and VIIIA with the known polyether polyols and polyester polyols. Further, radiation convertible urethane polymers can also be produced by the reaction of the previously described radiation convertible polyester polymers and radiation convertible polyether polymers with the known conventional organic polyisocyanates. All of these procedures introduce the radiation convertible norbornenyl group into the polymer backbone. P Other methods can also beused for producing radiation convertible urethane polymers containing the norbornene group in the po lymer backbone. Thus for instance fumaryl diisocyanate can be reacted with a conventional polyol to produce an unsaturated urethane polymer that is subsequently reacted with a cyclopentadiene, as follows:

CHCOOCHQCHQNC o HOMOH oHoooomomNoo l Step 1 [COOCHQCHZNHC O O -OOCNHGH2CHiOOC- The conventional polyols suitable for use in producing the radiation convertible urethane polymers, either (1) by reaction alone with a norbornene isocyanate of Formulas VIII or VIIIA or (2) by reaction with a mixture of isocyanates including at least one norbornene isocyanate of Formulas VIII or VIIIA or (3) in admixture with a radiation convertible polyester polymer or radiation convertible polyether polymer can be a hydroxylterminated polyester, a polyhydroxyalkane, a polyphenol, a polyoxyalkylene polyol, or the like, having a molecular weight of at least about 200. Among the polyols which can be employed one can include, among others, one or more polyols from the following classes of compostions, minor amounts of polyhydroxyalkanes can be present.

a. I-Iydroxyl-terminated polyesters;

b. Alkylene oxide adducts of polyhydroxyalkanes;

c. Trialkanolamines and alkylene oxide adducts thereof;

d. Alcohols derived from monoand polyamines by addition of alkylene oxides;

e. Non-reducing sugars and sugar derivatives and alkylene oxide adducts thereof;

f. Alkylene oxide adducts of aromatic amine/phenol/aldehyde condensation products;

g. Alkylene oxide adducts of phosphorus and polyphosphorus acids;

h. Polyphenols and alkylene oxide adducts thereof;

i. Polytetramethylene glycols;

j. Glycerides, such as castor oil and the halogenated derivatives thereof; and the like.

Illustrative hydroxyl-terminated polyesters are those which are prepared by polymerizing a lactone in the presence of an active hydrogen-containing starter as disclosed in US. Pat. No. 2,914,556.

Illustrative alkylene oxide addcts of polyhydroxyalkanes include, mong others, those alkylene adducts of ethylene glycol, propylene glycol, 1,3-dihydroxypropane, 1,3-dihydroxybutane, 1,4-dihydroxybutane, 1,4-, 1,5- and l,6-dihydroxyhexane, 1,2-, 1,3-, 1,4-, l,6- and 1,8-dihydroxyocatne, l,l-dihydroxydecane, glycerol, l,2,4-trihydroxybutane, l,2,6-trihydroxyhexane, 1,1 l -trimethylolethane, l,l 1 -trimethylolpropane, pentaerythritol, xylitol, arabitol, sorbitol, mannitol, and the like, having a molecular weight of at least 200; preferred are the adducts of ethylene oxide, propylene oxide, the epoxybutanes, or mixtures thereof.

Tow particularly preferred classes of alkylene oxide adducts of polyhydroxyalkanes are the ethylene oxide, propylene oxide, butylene oxide, or mixtures thereof, adducts of dihydroxyalkanes and of trihydroxyalkanes. Included are the alkylene oxide adducts of dihydroxyalkanes such as diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, tetrapropylene glycol, dibutylene glycol, glyercol, high molecular weight polyoxyethylene glycols, high molecular weight polyoxypropylene glycols, mixed ethylene-propylene glycols, mixed polyoxyethylene-polyoxypropylene glycols, and the like.

Another useful class of polyosl which can be employed includes the trialkanolamines and the alkylene oxide adducts thereof. Illustrative trialkanolamines in clude triethanolamine, triisopropanolamine, and tributanolamine. The alkylene oxide adducts thereof which can be employed are preferably those wherein the oxyalkylene moieties therein have from two to four carbon atoms.

Another useful class of polyols which can be employed includes the alkylene oxide adducts of monoand polyamines. The monoand polyamines are preferably reacted with alkylene oxides that have two to four carbon atoms, for example, ethylene oxide, 1,2- epoxypropane, the epoxybutanes, and mixtures thereof. Monoand polyamines suitable for reaction with the alkylene oxides include, among others, methylamine, ethylamine, isopropylamine, butylamine, benzylamine, aniline, the toluidines, the naphthylamines, ethylenediamine, diethylenetriamine, triethylenetetramine, l,3-butanediamine, 1,3- propanediamine, l,4butanediamine, 1,2-, 1,3-, 1,4-, l,5-, and l,6-hexanediamine, the phenylenediamines, the toluene diamines, the naphthalenediamines, and the like. Among the compounds of the above groups which are of particular interest are, among others N,N,N,N'-tetrakis(2-hydroxyethyl)ethylenediamine, N,N,N,N'-tetrakis(2-hydroxypropyl)ethylenediamine, N,N,N4N",N-pentakis-(Z-hydroxypropyl)diethylenetriamine, phenyldiisopropanolamine and higher alkylene oxide adducts of aniline, and the like. Others which deserve particular mention are the alkylene oxide adducts of unsubstituted or substituted aniline/formaldehyde condensation products.

A further class of polyols which can be employed includes the non-reducing sugars, the non-reducing sugar derivatives, and more preferably, the alkylene oxide adducts thereof wherein the alkylene oxides have from two to four carbon atoms, for example as disclosed in US. Pat. No. 3,073,788. Among the non-reducing sugars and sugar derivatives contemplated are sucrose, alkyl glycosides such as methyl glucoside, ethyl glucoside, and the like, glycol glycosides such as ethylene glycol glucoside, propylene glycol glucoside, glycerol glucoside, 1,2,6-hexanetriol glucoside, and the like.

A still further useful class of polyols includes the polyphenols, and preferably the alkylene oxide adducts thereof wherein the alkylene oxides have from two to four carbon atoms. Among the polyphenols which are contemplated are found, for example, bisphenol A, bisphenol F, condensation products of phenol and formaldehyde, more particularly the novolac resins, condensation products of various phenolic compounds and acrolein, the simplest mSmbers of this class being the 1,1 ,3-tris(hydroxyphenyl)propanes, condensation products of various phenolic compounds and glyoxal, glutaraldehyde, and other dialdehydes, the simplest members of this class being the l,l,2,2- tetrakis(hydroxyphenyl)ethanes, and the like.

Another desirable class of polyols includes the alkylene oxide adducts, preferably the ethylene oxide,

1,2-epoxypropane, epoxybutane, and mixtures thereof, adducts of aromatic amine/phenol/aldehyde condensation products. The condensation products are prepared by condensing an aromatic amine, for instance aniline, toluidine, or the like, a phenol such as phenol, cresol, or the like, and an aldehyde, preferably formaldehyde, at elevated temperatures in the range of, for example, from 60 to 180C. The condensation product is then recovered and reacted with alkylene oxide, using a basic catalyst e.g., potassium hydroxide) if desired, to produce the polyols. The propylene oxide and mixed propyleneethylene oxide adducts of aniline/phenol/formaldehyde condensation products deserve particular mention.

The alkylene oxide-adducts of the phosphorous and polyphosphorous acids constitute another useful class of polyols. Ethylene oxide, 1,2-epoxypropane, the epoxybutanes, 3-chloro-1,2-epoxyproane, and the like are preferred alkylene oxides. Phosphoric acid, phosphorous acid, the polyphosphoric acids such as tripolyphosphoric acid, the polymetaphosphoric acids, and the like are desirable for use in this connection.

Another useful class of polyols are the polytetramethylene glycols, which are prepared by polymerizing tetrahydrofuran in the presence of an acidic catalyst.

The polyols can have hydroxy] numbers which vary over a wide range. In general, the hydroxy numbers of the polyols employed can range from about 20, and lower, to about 1000, and higher, preferably, from about 30 to about 600, and more preferably, from about 35 to about 450. The hydroxyl number is defined as the number of milligrams of potassium hydroxide required for the complete hydrolysis of the fully acetylated derivative prepared from 1 gram of polyol. The

hydroxyl number can also be defined by the equation:

on 56.1 x 1000 Xf/m.w.

where OH hydroxy] number of the polyol f functionality, that is, average number of hydroxy groups per molecule of polyol m.w. molecular weight of the polyol.

The amount of polyisocyanate employed to produce the photosensitive urethane polymer is dependent, in part, upon such factors as the nature of the reactants, the nature of the enduse for the polyurethane product, and the like. In general, however, the total isocyanato equivalent to total reactive hydrogen equivalent i.e., total equivalent of alcoholic hydroxyl plus water, if water is employed in the formulation) is ordinarily such as to provideenough isocyanato equivalents to react with all reactive hydrogen equivalents present. Preferably, the ratio of isocyanato equivalents to reactive hydrogen equivalents is about 1.0 to 1.1 isocyanato equivalents per reactive hydrogen equivalent.

The photosensitive urethane polymers re prepared in the absence of blowing agentby weight the quasiprepolymer or the prepolymer technique when a noncellular product is desired. When cellular products are desired, either the one-shot or the quasi-prepolymer technique can be employed. These procedures are well known in the art.

Foaming can be accomplished by employing a small amount of water in the reaction mixture (for example,

from about 0.5 to 5 weight per cent of water, based on total weight of the reaction mixture), or through the use of blowing agents which are vaporized by the exotherm of the isocyanate-reactive hydrogen reaction, or by a combination of the two methods. All of these methods are known in the art. The preferred blowing agents are certain halogen-substituted aliphatic hydrocarbons which have boiling points between about 40C. and C., which vaporize at or below the temperature of the foaming mass. The blowing agents include, for example, trichloromonofluoromethane, dichlorodifluoromethane,

dichloromonofluoromethane, dichloromethane, trichloromethane, bromotrifluoromethane, chlorodifluoromethane, chloromethane, 1,1-dichlorol-fluoroethane, 1,l-difluoro-1,2,2-trichloroethahe,

chloropentafluoroethane, l-chloro- 1 -fluoroethane, l-

chloro-2-fluoroethane, 1,1,2-trichloro-l,2,2-

trifluoroethane, 1,1,1-trichloro-2,2,2-trifluoroethane, 2-chloro-1,l,1,2,3 ,3 ,4,4,4-nonafluorobutane, hexafluorocyclobutene, and octafluorocyclobutane. Other useful blowing agents include low-boiling hydrocarbons such as butane, pentane, hexane, cyclohexane, and the like. Many other compounds easily volatilized by the exotherm of the isocyanate-reactive hydrogen reaction also can be employed as is known in the art, including acetone, and the like. A further class of blowing agents includes the thermally unstable compounds which liberate gases upon heating, such as N,N'-

dimethyl-N,N-dinitrosoterephthalamide, ammonium bicarbonate, and the like.

The amount of blowing agent used will vary with the density desired in the foamed product. In general it may be stated that for grams of reaction mixture containing an average isocyanate/reactive hydrogen ratio of about 1:1, about 0.005 to 0.3 moles of gas are used to provide densities ranging from 30 to 1 pounds per cubic foot respectively.

Catalysts can be employed in the reaction mixture for accelerating the isocyanate-reactive hydrogen reaction. Such catalysts include a wide variety of compounds and illustrative thereof one can mention for example:

a. tertiary amines such as trimethylamine, triethylamine, N-methyl-morpholine, N-ethylmorpholine, N,N-dimethylbenzylamine, N,N-dimethylethanolamine, N,N,N',N'ltetramethyl-l,3- butanediamine, triethanolamine, 1,4-diazabicyclo[2.2.2]octane, and the like.

b. tertiary phosphoines such as trialkylphosphines,

dialkylbenzylphosphines, and the like;

c. strong bases such as the alkali and alkaline eartemetal hydroxides, alkoxides, and phenoxides;

. acidic metal salts of strong acids such as ferric chloride, stannic chloride, stannous chloride, antimony trichloride, bismuth nitrate and chloride, and the like;

e. chelates of various metals such as those which can be obtained from acetylacetone, benzoylacetone, trifluoroaeetylacetone, ethyl acetoacetate, salicylaldehyde, cyclopentanone-2-carboxylate, acetylacetoneimine, bis-acetylacetonaealkylenediimines, salicylaldehydeimine, and the like, with various metals such as Be, Mg, Zn, Cd, Pb, Ti, Zr, Sn, As, Bi, Cr, Mo, Mn, Fe, Co, Ni, or such ions as M00,++, UO,-H-, and the like;

f. alcoholates and phenolates of various metals such as Ti(OR),,, Sn(OR) Sn(OR) Al(OR) and the like, wherein R is alkyl or aryl, and the reaction products of alcoholates with carboxylic acids, beta-diketones, and 2-(N,N-dialkylamino)-alkanols, such as the well known chelates of titanium obtained by said or equivalent procedures;

g. salts of organic acids with a variety of metals such as alkali metals, alkaline earth metals, al. Sn, Pb, Mn, Co, Ni, and Cu, including, for example, sodium acetate, potassium laurate, calcium hexanoate, stannous acetate, stannous octoate, stannous oleate, lead octoate, metallic driers such as manganese and cobalt naphthenate, and the like;

h. organometallic derivatives of tetravalent tin, trivalent and pentavalent As, Sb, and Bi, and metal carbonyls of iron and cobalt. As is obvious to those skilled in the art, many other catalysts and solvents that have a catalytic effect can also be used.

Among the organotin compounds that deserve particular mention are dialkyltin salts of carboxylic acids,

, e.g., dibutyltin diacetate, dibutyltin dilaurate, dibutyltin maleate dilauryltin diacetate, dioctyltin diacetate,

dibutyltin-bis(4-methylaminobenzoate), dibutyltinbis(fi-methylaminocaproate), and the like. Similarly there may be used a trialkyltin hydroxide, dialkyltin oxide, dialkyltin dialkoxide, or dialkyltin dichloride. Examples of these compounds include trimethyltin hydroxide, tributyltin hydroxide, trioctyltin hydroxide, dibutyltin oxide, dioctyltin oxide, dilauryltin oxide, dibutyltin-bis(isopropoxide), dibutyltin-bis(2- dimethylaminopentylate), dibutyltin dichloride, dioctyltin dichloride, and the like.

The tertiary amines may be used as primary catalysts for accelerating the reactive hydrogen/isocyanate reaction or as secondary catalysts in combination with one or more of the above noted metal catalysts. Metal catalysts, or combinations of metal catalysts, may also be employed as the accelerating agents, without the use of amines. The catalysts are employed in small amounts, for example, from about 0.001 per cent to about 5 per cent, based on the weight of the reaction mixture.

It is also known to employ small amounts, e.g., about 0.001 to 5.0 percent by weight, based on the total reaction mixture, of an emulsifying agent such as a polysiloxane-polyoxyalkylene block copolymer having from about to 80 per cent by weight of siloxane polymer and from 90 to per cent by weight of alkylen'e oxide polymer, such as the block copolymers described in US. Pat. Nos. 2,834,748 and 2,917,480. Another useful class of emulsifiers are the nonhydrolyzable polysiloxane-polyoxyalkylene block copolymers. This class of compounds differs from the above-mentioned polysiloxane-polyoxyalkylene block copolymers in that the polysiloxane moiety is bonded to the polyoxyalkylene moiety through direct carbonto-silicon bonds, rather than through carbon-to-oxygen-to-silicon bonds. These copolymers generally contain from 5 to 95 weight per cent, and preferably from 5 to 50 weight per cent, of polysiloxane polymer with the remainder being polyoxyalkylene polymer. The copolymers can be prepared, for example, by heating a mixture of (a) a polysiloxane polymer containing a silicon-bonded, galogen-substituted monovalent hydrocarbon group, and (b) an alkali metal salt of a polyoxyalkylene polymer, to a temperature sufficient to cause the polysiloxane polymer and the salt to react to form the block copolymer. Although the use of an emulsifier is desirable to influence the type of foam structure that is formed, the foam products of the invention can be prepared without emulsifier.

Illustrative of photosensitive urethane polymers are the polyurethanes produced from the following reactant combinations. In this group of examples the parenthetical figure represents the percentage by weight based on the total weight of that particular class of reactants. The methods for producing urethane foams and elastomers are well known in the art; reference thereto can be made to Saunders and Frisch, Polurethanes, Parts I and I], published by lnterscience Publishers.

52. 5,6-bicyclo[2.2. l ]hept-Z-ene diisocyanate 1,2-propylene oxide adduct of glycerol to about 3000 average molecular weight and average hydroxyl number of 56 (Polyol A).

53. 5,6-diisocyanatomethylbicyclo[2.2. 1 ]hept-Z-ene 80/20 mixture of 2,4- and 2,6-tolylenediisocyanates (50) ethylene oxide addust ot glycerol to about 2500 molecular weight capped with 1,2-propylene oxide to a final average molecular weight of about 3000 (Polyol B).

54. 5,6-diisocyanatomethylbicyclo[2.2.l ]hept-2-ene 80/20 mixture of 2,4- and 2,6-tolylene diisocyanates Photosensitive Polyester No. 1, supra.

55. 5,6-diisocyanatomethylbicyclo[2.2.l ]hept-Z-ene 80/20 mixture of 2,4- and 2,6-tolylene diisocyanates (70) Photosensitive Polyether No. 36, supra.

56. 5,6-diisocyanatomethylbicyclo[2.2.l ]hept-Z-ene 80/20 mixture of 2,4- and 2,6-tolylene diisocyanates (70) hotosensitive Polyether No. 42, supra.

57. 5,6-diisocyanatomethylbicyclo[2.2.l ]hept-2-ene 80/20 mixture of 2,4- and 2,6-tolylene diisocyanates (70) Polyol A photosensitive Polyether No. 37 (25), supra.

58. 5,6-diisocyanatomethylbicyclo[2.2.l ]hept-Z-ene /20 mixture of 2,4- and 2,6-tolylene diisocyanates Photosensitive Polyether No. 36, supra.

59. 5,6-diisocyanatomethylbicyclo[2.2.l ]hept-Z-ene 80/20 mixture of 2,4- and 2,6-tolylene diisocyanates (50) Photosensitive Polyester No. 1, supra.

60. 5,6-diisocyanatomethylbicyclo[2.2.l ]hept-Z-ene 80/20 mixture of 2,4- and 2,6-tolylene diisocyanates (50) Photosensitive Polyether No. 36 (20), supra.

Polyol B (80).

61. Polymethylene polyphenylisocyanate Photosensitive Polyether No. 36, supra.

62. 80/20 mixture of 2,4- and 2,6-tolylene diisocanate Photosensitive Polyether No. 37, supra.

63. 80/20 mixture of 2,4- and 2,6-tolylene diisocyanate Photosensitive Polyester No. 6, supra.

64. 80/20 mixture of 2,4- and 2,6-tolylene diisocyanate Polyol A (65) Photosensitive Polyether No. 36 (35 supra.

The radiation convertible polyureas may be prepared by the reaction of a diamine norbornene (IV) alone or with other diamines and phosgene. The polyureas can also be produced by reaction of a dicarbamoyl chloride (bischloroformate) and a diamine norbornene (IV) or other diamine compound. The dicarbamoyl chloride can be prepared by reaction of a diamino norbornene (IV) or other diamine compound with an excess of phosgene. The polyureas can be prepared by reactionof a norbornene diisocyanate (VIII or VIIIA) alone or in combination with other diisocyanates and a diamino norbornene alone or in combination with other diamino compounds. Further, the polyureas can be prepared by reaction of a diamino norbornene (IV) with other known diisocyanates, either alone or in admixture with other known diamines.

The polyureas can be produced by solution polymerization at moderate temperatures, this method involves dissolving each complementary reactant, for instance, a diamine and a diisocyanate or a dicarbamoyl chloride in separate portions of the same solvent substantially inert to the reactants, and the mixing of these solutions at a temperature of from to 120C. to form high molecular weight polymer. For this reaction the total number of reactive amine groups should not differ from the total number of isocyanate groups by more than about percent.

The solvents which may be used in this reaction are any one of those which areinert to the reactants and polymer and will dissolve both reactants at the reaction temperature. Among these may be mentioned acetone, methylene chloride, chloroform, dimethylacetamide, N-methylpyrrolidone; dimethylcyanamide, benzene, nitromethane, chlorobenzene, dimethylsulfoxide, etc. Especially advantageous are solutions of dimethylformamide or dimethylacetamide containing up to about 5 percent of lithium chloride. ,In the preferred embodiment, the reaction is preformed at room temperature with the reactan ts being dissolved in'a solvent for the polymer to such an extent that the resulting polymer solution contains at least 5 percent, but preferably percent or more, of the polymer and is suitable for the spinningof fibers or casting of films with little or no further concentration.

Illustrative radiation convertible polyureas are the polymers produced from the following combinations of reactants. The parenthetical figure if the mole per cent of that particular compound charged when a mixture of that class of compound is used, thiws mole per cent is based on the total molar amount of that class of compound involved, whether it be diamine or diisocyanate.

65. Bis(2-isocyanatoethyl)bicyclo[2.2. l ]hept-Z-ene- 5,6-dicarboxylate 1,6-I-lexanediamine 66. Bis(4-isocyanatophe nyl)methane A direct method for the production of vinyl backbone radiation convertible polymers can also be used. In this method a norbornadiene, substituted or unsubstituted, is copolymerized with a polymerizable ethylenically unsaturated monomer, that contains the polymerizable group. These ethylenically unsaturated monomers are defined infra, through the list is not all inclusive. The monomers are well known as are the processes for their polymerization; conventional polymerization procedures known to those skilled in the art are used to produce the vinyl backbone radiation convertible polymers.

PENDANT RADIATION CONVERTIBLE POLYMERS Radiation convertible polymers in which the norbornenyl group is pendant to the polymer backbone are readily produced by conventional procedures. This class of radiation convertible polymers contains the norbornenyl ring attached to the polymer chain via a monovalent bond as illustrated below.

-Polymfl' backbone Connectlng Link For the purposes of this invention such polymers will be known by the term pendant radiation convertible polymers.

These radiation convertible polymers can be produced directly by polymerization of a substituted norbornene compound in which the substituent is a polymerizable ethylenic group of the formula either alone or in combination with other polymerizable ethylenically unsaturated monomers. They can also 23 be produced by modification ofa preformed polymer.

The polymerizable ethylenically unsaturated norbornene compounds suitable for use in the production of radiation convertible polymers by the direct polymerization process are those of the formula and epoxides thereof wherein the oxirane ring of said epoxides is located in the chain, in which R is hydrogen, alkyl of from one to three carbon atoms or chlorine; m is an integer having a value of from to 4; X is a keto group an ether linkage -O-, an ester group an amide group or urethane group and y is 0 or 1. The C,, 1-l,,,, groups can be linear or branched.

The following subgeneric classes fall within the scope of Formula 1X. The symbol Norb" represents the norbornenyl radical and p has a value of from 1 to 4.

The following table lists formulas of specific compounds falling within the scope of Formula IX. This tabulation is illustrative only and is not tob be considered a complete tabulation of all possible compounds. 1n the table the norbornenyl moiety is not portrayed; the table sets forth that portion represented by the -C,,,H,,,,XC,,.H,,,,-CR=CH, section of the compound only, with the units connected in the order shown to the norbornenyl nucleus.

As previously indicated the polymerizable ethylenically unsaturated norbornene compounds of Formula lX can be copolymerized with other known polymerizable ethylenically unsaturated comonomers that also contain the polymerizable group. Illustrative thereof one can mention the alphaolefins containing from two to about eight carbon atoms such as ethylene, propylene, butene-l, and the like; acrylinc acid and its derivatives, such as acrylonitrile, methacrylonitrile, acrylamide, methacrylamide, methacrylic acid, methylmethacrylate, ethyl methacrylate, ethyl acrylate, and the like; the vinyl halides such as vinyl chloride, vinylidene chloride, vinyl fluoride, and the like; the vinyl esters such as vinyl acetate, vinyl butyrate, vinyl benzoate, and the like; the vinyl ketones such as isopropenyl methyl ketone, vinyl phenyl ketone, vinyl methyl ketone, alpha-chlorovinyl methyl ketone, and the like; the vinyl thioethers such as vinyl ethyl sulfide, vinyl ptolyl sulfide, divinyl sulfide, and the like. Other polymerizable comonomers which can be copolymerized are styrene, divinyl sulfone, vinyl ethyl sulfone, vinyl ethyl sulfoxide, vinyl sulfonicacid, sodium vinyl sulfonate, vinyl sulfonamide, vinyl pyridine, N-vinyl pyrollidone, N-vinyl carbazole, and the like. The comonomers can be used individually or in a mixtures containing two or more thereof.

The pendant radiation convertible polymers can be homopolymers of the ethylenically unsaturated norbornene compounds of the formula IX. They can also be copolymers thereof with one or more ethylenically unsaturated comonomers wherein the comonomers content can be as high as 98 weight per cent. Preferably, however,the comonomer content will be from about 60 to about weight per cent.

The direct polymerization can be carried out by any of the known catalytic procedures, in bulk, in a solvent, by an aqueous emulsion process, by an aqueous dispersion process, etc. Those skilled in the art are well familiar with such processes and the manner in which they are conducted. Thus, for example, the polymerization can be carried out in the presence of a free radical initiator at atmospheric or superatmospheric pressures up to 60,000 psig. or higher, and at temperatures of from about 30 C. to about 350C. In peroxides, persulfates, perborates, percarbonates, peroxydicarbonates, etc. are known catalysts classes, as is oxygen itself. Illustrative catalysts are hydrogen peroxide, persuccinic acid, lauroyl peroxide, butyryl peroxide,

benzoyl peroxide, acetyl peroxide, peracetic acid, diisopropyl peroxydicarbonate, lauroyl peroxide, sodium persulfate, sodium perborate, sodium percarbonate, and the like. The concentration of the free radical catalyst can vary from 10 parts per million to 5 about 5,000 parts per million, preferably from about 25 parts per million to about 250 parts per million, based on the monomers feed charged. The emulsion and dispersion processes are generally carried out at from 30C. to about 100C. using either a free radical catalyst or a redox catalyst system such as the potassium persulfate-sodium bisulfite, hydrogen peroxide-iron salts, cumene hydroperoxide ferrour salts, peracetic acid alkyl mercaptan redox systems; these processes 15 can be reacted with a norbornenyl compound having a 2 reactive group thereon. This is shown below by the reaction of the hydrolyzed copolymer of ethylene and vinyl acetete with 5-isocyanatomethylbicyclo{2.2.1 ']hept-2-ene.

LCHECHQ One can also react the hydroxyl group of the above hydrolyzed copolymer with an acid chloride such as thea cid chloride of bicyclo[2.2.l]hept-2-ene-5-carboxylic acid to produce a radiation convertible 45 polymer having the pentant group A phenoxy pendant radiation convertible/polymer can be produced as shown by the following reaction sequence The phenolic pendant radiation convertible polymers are produced in a somewhat similar manner Polyamides can be reacted with the ester chloride as follows The norbonenyl group can be formed on the polymer by a Diels-Alder reaction, as illustrated by the following equations:

- ClIlClI----- omcn A still further method is the dehydrochlorination of a chlorinated norbornane:

CI-IzCH All of the indicated reactions can be carried out by conventional, known chemical reactions that re readily apparent to one skilled in the art. This listing is not to be considered limitative of the methods that can be used; it is submitted for illustrative purposes only.

The concentration of the norbornenyl group in the radiation convertible polymer, whether it be a backbone radiation convertible polymer or a pendant radiation convertible polymer, can vary from about one mole per cent up to 100 mole per cent. Preferably it is at least about 10 mole per cent.

The radiation convertible polymers can be blended with other polymers if desired, for example, vinyl polymers, polyolefins, polyvinyl halides, polyacylonitrile, polyesters, polyamides, polyureas, polyurethanes, polyalkylene oxides, polycarbonates, polyt'ormaldehydes, polystyrenes, polyacrylates, polyvinyl esters, polyvinylidene halides, polyethers, polysaccharides, regenerated wool, silicone polymers, polysulfides, polysulfones, formaldehyde resins, and the heterocyclic polymers such as polybenzimidazoles, polypyromellitamides, polybenzoazoles, and the like. in such instances, the concentration of radiation convertible in the blend should be such that the blend contains about 5 weight per cent radiation convertible polymer, and can be up to about 99 weight per cent. In some instances the concentration can be lower. The blends can be produced by any conventional blending procedure, for example by milling, solution blending, etc.

The following examples further serve to describe the invention.

EXAMPLE 1 A 300 gram sample of an ethylene/vinyl acetate copolymer having about 16.2 weight per cent vinyl acetate content and a melt index of 2.9 dgm/min. was dissolved in 1400 grams of toluene by heating the mixture in a three liter flask fitted with a reflux condenser. Methanol, 129 grams, was added to the stirred solution at 70C. and after the reaction mixture had cooled to 60C., 23.2 grams of a 25 per cent methanolic solution of sodium rnethoxide was added. The solution was refluxed for three hours, cooled and poured into methanol. The hydrolyzed copolymer was recovered by filtration and reslurried in methanol until the methanol filtrate was neutral. The ethylene/vinyl alcohol copolymer obtained was vacuum dried and infra-red analysis established that hydrolysis had occurred to the extent of about 97 per cent.

A. 100 grams of the ethylene/vinyl alcohol copolymer (equivalent to 0.204 mole of vinyl alcohol) was charged to a flask. Benzene, 700 ml., was added and about per cent of the solvent was azeotropicall y distilled to remove traces of water that might be present. The solution was cooled to 70C. and a few drops of dibutyl tin dilaurate were added. 5-lsocyanatomethyl-bicyclo[2.2.1]hept-Z-ene, 9.6 grams, pr oduced as disclosed in US. Pat. No. 3,222,387, was added and the solution was agitated for 30 minutes at a temperature of C. This amount of S-isocyanatomethylbicyclo[2.2.l ]hept-2-ene was sufficient to react withabout 31 mole per cent of the available free hydroxyl groups and form the urethane linkage. 1nfrared spectroscopy showed that all of this isocyanate had reacted. The remainder of the free hydroxyl groups were reacted with an excess of methyl isocyanate, 12.5 grams, by refluxing for an additional hour. The resulting radiation convertible polymer was precipitated and washed in methanol and then dried in a vacuum oven at 50C. The polymer contained the following groups in the molecule, with about8 per cent by weight of the polymer being the N-(5-norbornen-2-ylmethyl)carbamyloxy group.

-C ID0112 emon; 1

LdooNnol-ni B. In a second run 67 grams of the ethylene/vinyl alcohol copolymer was reacted with 14 grams of 5-isocyanatomethylbicyclo-[2.2.1]hept-2-ene and 10 grams of emthyl isocyanate to produce a radiation convertible polymer having an N-(5-norbornen-2-ylmethyl)-carbamyloxy group content of about 17 weight per cent. The procedure used was described above.

C. A control polymer was prepared which contained about 18.4 weight per cent N-methylcarbamyloxy group and no N-(5-norbornen-2-ylmethyl)carbamyloxy group. This was produced by reacting the ethylenevinyl alcohol polymer with methyl isocyanate only.

Portions of polymer samples B and C were blended by milling with 0.5 weight per cent acetophenone as the photosensitizer. All of the polymers both with and without photosensitizer, were then molded into plaques 5 inches in diameter and 0.02 inch thick. Portions of all of the plaques were all completely soluble in hot benzene prior to irradiation.

All of the plaques were exposed to a watt medium pressure quartz mercury arc. Samples were cut from the exposed portions at appropriate intervals and the extent of crosslinking was determined by extraction with hot benzene to constant weight. The results are tabulated below; the figures in the table represent the weight per cent insoluble polymer after exposure for the period of time, in hours, indicated in the left hand column. It is evident that the radiation convertible polymers of this invention A and B showed that a much greater amount of crosslinking had occurred than in the control C.

a With photosensitizer b Without photosensitizer EXXMPLEZ A. Into a 500 ml. five-neck flask equipped with an electric stirrer, brine-cooled reflux condenser, dropping funnel, thermometer, and nitrogen ebullition tube there was placed 135 grams of deaerated water, 15 grams of an anionic sulfactant, 70 grams of ethyl acrylate, 28 grams of methyl methacrylate, 2 grams of 5- norbornen-Z-ylmethyl acrylate and 2grams of cumene hydroperoxide. The reaction was initiated by the addition of 1 ml. of per cent aqueous ferrous sulfate heptahydrate solution; the temperature rose to about 40C. within about 5 minutes. This temperature was maintained for l /hours by the slow dropwise addition of a 10 per cent aqueous sodium bisulfite solution. The reaction was stopped before the polymerization had run to completion by cooling the latex with an ice bath and the addition of 3 ml. of a 10 per cent aqueous hydroquinone solution. The radiation convertible terpolymer in the latex contained the following groups in the molecule at a weight ratio of about 7018222, respectively:

B. In a manner similar to that described above, a control polymer was produced which did not contain 5- norbornen-Z-ylmethyl acrylate. The copolymer contained about 70 weight per cent polymerized ethyl acrylate and about 30 weight per cent polymerized methyl methacrylate. In the preparation of this control sample, the sodium bisulfite addition was continued until the reaction was judged complete.

To one hundred gram portions of each latex there was added one gram of an emulsion containing the photosensitizer acetophenone. This emulsion contained 50 grams of acetophenone, 5 grams of the nonyl phenyl polyethylene glycol ether surfactant (having an average of 10.5 moles ethylene oxide) and 195 grams of water. Two films from each of the latex compositions were cast on glass plates and allowed to dry in the dark. One film of each pair was stored in the dark, while its mate was irradiated by exposure to two 40 watt Westinghouse Fluorescent Sunlamps at a distance of 4 inches for 3 days. The extent of crosslinking after 3 days was determined by testing for insolubility by shaking overnight in 49 time the sample weight of a 90:10 acetone: water solution. The results are set forth below Percent lnsolubility Sample Dark Storage Irradiated 2A 5.4 87.9 28 0 14.7

EXAMPLE 3 Grams of an ethylene/vinyl aclohol copolymer (produced by the hydrolysis of an ethylene/vinyl acetate copolymer as described in Example 1 and equivalent to 0.125 mole of vinyl alcohol), 500 ml. of benzene and 10 ml. of pyridine were charged to a one liter flask equipped with a stirrer, a condenser (attached to a nitrogen supply and bubbler), a dropping funnel, and a thermowell with a thermocouple. Fifty ml. of the solution were azeotropically distilled to remove any traces of water that might have been present. Then 20.5 grams of 5-chloroformyl-2-norbornene was added over a 15 minute period to the refluxing solution. The mixture was refluxed for an additional hour, cooled to 40C. and transferred to a large beaker. Methanol was slowly added with stirring until the solution was cloudy, then 2 liters of methanol was added quickly The ethylene/vinyl S-norbornene-Z-carboxylate copolymer was filtered, washed three times in methanol and dried. The yield was 63.3 grams. Elemental analysis for carbon was 83.14 per cent; theoretical value is 83.63 per cent. The radiation convertible copolymer contained the following groups:

CHZCHZ CHCIIz Time, hr. Percent Insolubilization 0.5 9.6

Film samples of the above were also radiated with an electron beam from a 1 mev Van de Graaff accelerator and the extent of crosslinking determined at different dosages. The film was radiated in a sealed polyethylene bag under nitrogen, at room temperature. For control purposes, a film from an ethylene/vinyl acetate copolymer B (85.15 weight ratio) was similarly treated. The extent of crosslinking that was achieved by Van de Graaff irradiation was determined by extraction of their radiated copolymer with benzene at 60C. for 100 hours. The ethylene/vinyl 5-norbornene-2-carboxylate copolymer was 53.3 per cent insoluble after a radiation dose of 0.1 mrad; with a 0.5 mrad dose the copolymer was 82.1 per cent insoluble; and with a l mrad dose it was 92.3 per cent soluble; 2 mrads yielded a copolymer that was 95.8 per cent insoluble. The ethylene/vinyl acetate copolymer, however, showed little crosslinking with a l mrad dose; the per cent insolubilization was only 1 per cent; with 2 mrads this copolymer was only 26.6 per cent insoluble; and with a massive dosage of 7 mrads only 79.4 per cent insolubilization was achieved. These results are tabulated below for ready comparison.

Percent lnsolubiliization mrads Polymer A Polymer 13 0.1 53.3

Polymer A ethylene/vinyl -norbomene-2-carboxylate copolymer. Polymer B ethylene/vinyl acetate copolymer.

The data clearly reveals the remarkable enhancement of crosslinking at low dosages achieved by the radiation convertible copolymer containing the pendant norbornenyl groups. Thus, at l mrad, where the control copolymer, Polymer B, was crosslinked only to the extent of l per cent, the norbomenyl-containing radiation convertible copolymer, Polymer A, was almost completely crosslinked, to the extent of 92.3 per cent.

EXAMPLE 4 A series of pendant radiation convertible polymers was produced using different poly(vinyl alcohol) resins. The poly-(vinyl alcohol) was reacted with S-norbornen-Z-ylmethyl isocyanate. In some instances methyl isocyanate was also reacted with the polymer, In gneeral the reactions were carried out as follows:

A flask equipped with a stirrer, condenser, dropping funnel and temperature recording means was charged with 44 grams of the selected poly(vinyl alcohol) and 400 grams of diemthylformamide. The mixture was heated to 90C., cooled to 70C. and two drops of dibutyltin dilaurate were added. After further stirring for several minutes, 5 grams of methyl isocyanate was added through the dropping funnel in those instances in which it was used. Fifteen minutes after completion of the methyl isocyanate addition, the indicated amount of S-norbornen-Z-ylmethyl isocyanate was slowly added at a rate to maintain the reaction temperature at 75C. and the reaction mixture was stirred at 70C. for another hour. The polymer was filtered, washed once with hexane, twice with acetone, and then vacuum dried at 50C.

The vinyl alcohol/vinyl N-(5-norbornen-2-ylmethyl)- carbamate radiation convertible copolymer produced contain the following groups:

The radiation convertible terpolymers produced with the further addition of methyl isocyanate additionally contain thegroup;

enore LOOCNHCH=J contain up to about 30 weight per cent of the vinyl N- (5-norbomen-2-ylmethyl) carbamate are soluble in hot water or in a 50-50 by volume ethanol-water mixture; those copolymers containing more than 30 weight per cent of the vinyl N-(5-norbornen-2-ylmethyl)carbamate group were not soluble in water but produced dispersion or emulsions in the ethanol-water mixture. The films were readily cast from the aqueous solutions or emulsions. The cast films were irradiated with a watt medium-pressure quartz mercury arc for the indicated period of time and the extent of crosslinking was determined by extraction with the ethanol-water mixture at the boil. The results are tabulated below:

Polyvinyl alcohol Mole percent hydrolyzed Percent insoluble after irradiation Weight percent in resin Norbornenyl compoun (1 Weight percent in resin Red.

vise. CHaNCO 1 hr. 10 hr.

Determined from a 0.2 percent solution in water at 30 C. *"5-norbornen-2-ylmethyl isocyanate.

The insolubilization and crosslinking of the radiation convertible polymers was completely unexpected and unobvious since the prior art had previously taught that polyvinyl alcohol degrades by chain fission when exposed to ionizing or ultraviolet radiation (K. Tabakura, G. Takayama and J. Ukida, Journal Applied Pplymer Science, Vol. 9, page 3217, 1965). The prior art has also taught that exposure to as much as 1100 mrad of gamma radiation will not in solubilize polyvinyl alcohol (I. Sakurada and S. Matsuzama, Kobunshi Kagaku, Vol :17, page 693, 1960; C.A. 55.25728c).

EXAMPLE 5 Percent lnsolubilization Dose, mrads Copolymer Control Ethylene/vinyl 5morbomene-Z-carboxylatc copolymer. Ethylene/vinyl acetate copolymer.

The data shows that the radiation convertible copolymer was essentially completely crosslinked with a dose of about 0.6 mrad; 30 times as much radiation, i8 mrad, was necessary to give the same amount of crosslinking in the control. The data also shows that while essentially complete crosslinking of the radiation convertible polymer was obtained with a dose of less than about 1 mrad, the control copolmer showed essentially no corsslinking whatsoever at this dosage rate.

EXAMPLE 6 A series of vinyl alcohol/vinyl N-(-norbornene-2-ylmethyl)carbamate radiation convertible copolymers was produced in a manner similar to that described in Example 4. The vinyl alcohol polymer used as the starting material had a reduced viscosity of 0.3 as determined from a 0.2 per cent aqueous solution at 30C. The amounts of 5-isocyanatomethyl-Z-norbornene used were varied to produce radiation convertible copolymers which contained 29.0, 43.7 and 58.6 weight per cent 98.5, 16.7 and 22.2 mole per cent) of vinyl N-(S-norbornen-2-ylmethyl)carbamate. Clear films, about 2 to 5 mils thick, of these copolymers were irradiated with ultraviolet light from a 100 watt medium-pressure mercury arc. Samples were periodically cut from the films and the extent ofinsolubilization and corsslinking was determined as disclosed in Example 4. The data indicated that crosslinking occurred at a faster rate and also to a greater extent as the vinyl N-(S- norbornen-Z-yl-methyl)carbamate content was increased. The data in the following table sets forth the maximum crosslinking achieved with each film and the time required to reach it; further radiation did not result in any further appreciable corsslinking.

Norborneyl Content A. 5-Norbornene-2,B-dicarboxylic anhydride, 328 grams, and propylene glycol, 167 grams, were charged to a 1 liter 4-neck, round bottom flask fitted with an air-driven paddle stirrer, thermometer, a 12 inch long column packed with Raschig rings and attached to a stream condenser, and a nitrogen sparger. The flask was heated to 200C. and held at this temperature for 6 hours. The radiation convertible polyester was a light yellow, slightly tacky solid with an acid number of 28.8.

To 50 grams of this polyester there was added 21.5 grams of styrene and 7 milligrams of hydroquinone and the mixture was rolled overnight to effect solution of the resin in the styrene. Steel panels, 2% by 6 inches, were coated with the solution and they were irradiated at a distance of 4 inches with a 100 watt medium-pressure mercury arc in a nitrogen atmosphere. The amount of curing was determined by boiling the panel in toluene for 10 minutes and visually observing the amount of material removed. After 10 minutes irradiation, all the polyester was washed off the panel. One hour's irradiation, however, was sufficient to crosslink the coating so that the refluxing toluene had no effect.

B. Toluene, 250 milliliters, pyridine, 59.3 grams, and polyethylene glycol of molecular weight 411, 100.75 grams, were charged to a 500 milliliter 4-neck round bottom flask fitted with an air driven paddle stirrer, thermometer, reflux condenser and dropping funnel. 5- Norbornene-2,3-dicarboxylic acid chloride was added rapidly by means of the dropping funnel to the stirred reaction mixture. The temperature rose spontaneously to C. Heat was applied and the mixture was refluxed for one hour, cooled, washed several times with water and then dried over anhydrous magnesium sulfate. The radiation convertible polyester was recovered as a residue produce after stirpping off the solvents.

Exposure of glass panels coated with the radiation convertible polyester to a watt medium-pressure mercury arc resulted in crosslinking as determined by the amount of solubilization in toluene and established that styrene was not the cause of the crosslinking. The data are given in the following table.

Irradiation Time, Hours Percent lnsolubilization Further irradiation did not result in furtheappreciable corsslinking.

EXAMPLE 8 5,6-Dl(hydroxymethyl)-2-norbornene, 30.8 grams, was placed in a resin reactor equipped with stirrer, dropping funnel and nitrogen purger. The reactor was heated by an external oil bath to C., the nitrogen purge was begun, and, with vigorous stirring, hexamethylene-l,6-diisocyanate, 33.64 grams, was added over a period of 1.5 hours. During this period, the temperature was gradually raised to C. The resulting backbone radiation convertible urethane polymer was clear and softened at about 120C. Plaques, meltpressed form the urethane polymer, were tough and transparent.

A 15% solution of the polymer was prepared in 1 1 volume chloroform-ethanol solution. Films cast onto polytetrafluoro ethylene films were clear, transparent and flexible. The polymer had repeating units of the structure:

F i TOCHz CHzOCNI-ICaI-IMNHCJ Sample strips were cut from a 5 inl plaque (about 20 mils thick and irradiated with a 100 watt medium pressure mercury arc in a nitrogen atmosphere. At specified time intervals, about 0.5 gram pieces were reomoved, placed in wire gauze cups, weighed and extracted in sealed bottles at 60C. with a chloroformethanol mixture (100 ml., 1:1 v/v). After four days the gauze cups and contents were removed, dried and weighed again. After weighing, the gauze cups were put in jars and the process repeated using fresh solvent and a 2 days extraction period. The results are tabulated below:

Hours 01' Percent Radiation lnsolubilization 5 8.7 10 23.6

EXAMPLE 9 100 Grams of cellulose acetate (38.3 per cent acetyl content) and 1 liter of methyl ethyl ketone were charged to a 2 liter resin flask equipped with a stirrer, a condenser (attached to a nitrogen supply and bubbler), a funnel, and a thermowell with thermocouple. The

solution was heated to 60C. and two drops of dibutyl ble hydroxyl groups had been converted to carbamate groups. Irradiation of a cast film from the radiation convertible polymer with high energy electrons as in Example 78 and determination of the amount of insolubilization gave the results tabulated below:

Percent lnsolubilization Dose, Megarad (Acetone at 60) 0.024 0.0

cCast films of the polymer could also be crosslinked by exposure to a 100 watt medium pressure mercury arc.

These results are shown in the following table:

Percent lnsolubilization Exposure Time, Hours (Acetone at 60C.)

Prior to irradiation, both cellulose acetate and the cellulose acetate N-(S-norbornen-2-ylmethyl)carbamate radiation convertible polymer were completely soluble in acetone.

EXAMPLE l0 Grams of vinyl chloride/vinyl acetate/vinyl alcohol terpolymer (of weight ratio 91:3:6, respectively), and 600 milliliters of ethylene dichloride were charged to a 1 liter resin flask equipped with a stirrer, a distillation head with a condenser (attached to a nitrogen supply and bubbler), a dropping funnel, and a thermowell with thermocouple. 50 Milliliters of the solution were azeotropically distilled to remove any traces of water that might have been present. Firtst, two drops of dibutyl tin dilaurate and then 20.0 grams 0 S-norbornen-Z- ylmethyl isocyanate were added over a minute period to the solution at 70C. After one hour, the temperature was raised to reflux and maintained until an infrared spectra of the reaction mixture showed complete reaction of the isocyanate hours). The solution was cooled and transferred to a large beaker.

Methanol was added slowly with stirring until the solution was cloudy, then 2 liters of methanol was added quickly. The vinyl chloride/vinyl acetate/vinyl N-(5- norbornen-Z-ylmethyl)-carbamate terpolymer was filtered washed three e times with methanol and dried in a vacuum oven at C. Elemental analysis indicated complete conversion of available hydroxyl groups to carbamate. Irradiation of 15 mil cast films with an electron beam from a l mev Van de Graaff as in Example 3 and determination of the amount of insolubilization gave the following results:

Percent lnsolubilization Dose, megarad (Ethylene dichloride at 60C) 0.68 0.0 0.28 l7.6 0.49 45.8 1.46 79.1 7.32 96.2 l4.7 100.0

Films of this material could also be crosslinked by irradiation with ultraviolet light from a 100 watt-medium-pressure mercury arc. This data is shown in the following table:

Percent lnsolubilization Exposure Time, Hours (Ethylene dichloride at 60C) Further exposure to the mercury arc did not result in additional insolubili zation, since the polymer, being light sensitive, showed signs of decomposition upon continued prolonged exposure to UV light.

EXAMPLE 1 l A 4 per cent solution in benzene of the radiationconvertible polymer described in Example 3 was used to treat swatches of 100 percent wool worsted, cotton print cloth (x80), and 50/50 Dacroncotton blend fabric by padding. These swatches and untreated control swatches were irradiated under nitrogen with high energy electorns from a 3 mev Van de Graaf accelerator. They were tested after irradiation for Elmensdorf Tear Strength (ASTM D 1424-59), Instron Break in the warp direction (ASTM D l682-59-T), Stiffness- Cantilever (ASTM D 1388-55-7), Shrinkage (AATCC 99-1962-T) and Wash and Wear properties (AATCC 88A-l964T). The results of the tests, the weight of radiation convertible polymer added on in the treatment and the radiation dosage are given in the following table.

In the tests, high values are preferred for the Tear Strength, Instron Break and Wash and Wear tests; low values are preferred for the stiffness and shrinkage tests. The results show an over-all improvement in the cloth properties.

wooL FAB RIC Warp instron Shrinkage Tear brea strength Warp dir., Area Dosage warp dir., percent total percent 5 Add-011 percent mrad. gms. Lbs. elong. Stifiness percent washes Control 0 0 2, 030 E1 60 3. g 20. 7 36 3.0 1, 780 21 60 3. 2 21. s Percent: 

